Agar and Gellan Gum are biocompatible polymers extensively used in several fields of tissue engineering research (e.g. tissue replacement, tissue support, tissue mimicking), due to their mechanical behaviour effectively representative of actual biological tissues. Since mechanical properties of artificial tissues are related to biocompatibility and functionality of medical implants and significantly influence adhesion, growth and differentiation of cells in tissue-engineering scaffolds, an accurate characterization of Young׳s modulus and relaxation time processes is needed. In this study, the strain-rate and temperature dependent material properties of Agarose and one among the numerous kind of Gellan Gum commercially available, known as Phytagel®, have been investigated. Nine hydrogel samples have been realized with different mechanical properties: the first one Agar-based as a reference material, the further eight samples Gellan Gum based in which the effect of dispersed solid particles like kieselguhr and SiC, as enhancing mechanical properties factors, have been investigated as a function of concentration. Stress-strain has been investigated in compression and relaxation time has been evaluated by means of the Kohlrausch-Williams-Watts time decay function. Mechanical properties have been measured as a function of temperature between 20°C and 35°C and at different strain rates, from ~10-3s-1 and ~10-2s-1 (or deformation rate from ~0.01mms-1 to ~0.1mms-1). From experimental data, the combined temperature and strain-rate dependence of hydrogels Young׳s modulus is determined on the basis of a constitutive model. In addition to a dependence of Young׳s modulus on temperature, a remarkable influence of strain-rate has been observed, especially in the sample containing solid particles; in same ranges of temperature and strain-rate, also relaxation time variations have been monitored in order to identify a possible dependence of damping properties on temperature and strain-rate. The result is the impossibility to determine univocally mechanical properties of studied biomaterials without a proper definition of boundary conditions at which they have been obtained.

Strain-rate and temperature dependent material properties of Agar and Gellan Gum used in biomedical applications / Schiavi, Alessandro; Cuccaro, Rugiada; Troia, Adriano. - In: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS. - ISSN 1751-6161. - 53:(2016), pp. 119-130. [10.1016/j.jmbbm.2015.08.011]

Strain-rate and temperature dependent material properties of Agar and Gellan Gum used in biomedical applications

Schiavi Alessandro;Cuccaro Rugiada;Troia Adriano
2016

Abstract

Agar and Gellan Gum are biocompatible polymers extensively used in several fields of tissue engineering research (e.g. tissue replacement, tissue support, tissue mimicking), due to their mechanical behaviour effectively representative of actual biological tissues. Since mechanical properties of artificial tissues are related to biocompatibility and functionality of medical implants and significantly influence adhesion, growth and differentiation of cells in tissue-engineering scaffolds, an accurate characterization of Young׳s modulus and relaxation time processes is needed. In this study, the strain-rate and temperature dependent material properties of Agarose and one among the numerous kind of Gellan Gum commercially available, known as Phytagel®, have been investigated. Nine hydrogel samples have been realized with different mechanical properties: the first one Agar-based as a reference material, the further eight samples Gellan Gum based in which the effect of dispersed solid particles like kieselguhr and SiC, as enhancing mechanical properties factors, have been investigated as a function of concentration. Stress-strain has been investigated in compression and relaxation time has been evaluated by means of the Kohlrausch-Williams-Watts time decay function. Mechanical properties have been measured as a function of temperature between 20°C and 35°C and at different strain rates, from ~10-3s-1 and ~10-2s-1 (or deformation rate from ~0.01mms-1 to ~0.1mms-1). From experimental data, the combined temperature and strain-rate dependence of hydrogels Young׳s modulus is determined on the basis of a constitutive model. In addition to a dependence of Young׳s modulus on temperature, a remarkable influence of strain-rate has been observed, especially in the sample containing solid particles; in same ranges of temperature and strain-rate, also relaxation time variations have been monitored in order to identify a possible dependence of damping properties on temperature and strain-rate. The result is the impossibility to determine univocally mechanical properties of studied biomaterials without a proper definition of boundary conditions at which they have been obtained.
File in questo prodotto:
File Dimensione Formato  
aleschiavi.pdf

non disponibili

Tipologia: Versione editoriale
Licenza: Non Pubblico - Accesso privato/ristretto
Dimensione 4.95 MB
Formato Adobe PDF
4.95 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Manuscript_Strain-rate (2).pdf

accesso aperto

Tipologia: Documento in Post-print
Licenza: Creative Commons
Dimensione 1.34 MB
Formato Adobe PDF
1.34 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11696/29943
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 35
  • ???jsp.display-item.citation.isi??? 28
social impact